Apparatus for annealing silver or other metals.



N0. 700,|0l. Patented May 13, I902.

' c. STICKNEY. I

APPARATUS FOR ANNEALING SILVER OR OTHER METALS.

(Application filed July 1, 1901.)

(No Model.)

2 Shaetr-Sheai I.

I m: Nonms PETERS 00., Pno'rcuuwu.v WASHINGTON, 0, c4

N0. 700,!0l. A Patented May l3, I902.

c. STICKNEY. APPARATUS FOR ANNEALING SILVER OR OTHER METALS.

(Application filed July 1, 1901.)

(No Model.)

UNITE? A-TATES ATT CALEB STICKNFY, NEWISURYPQRT, MASSACHUSETTS, ASSIGNOR TO TOI/VLE MANUFACTURING COMPANYfOF NEWBURYPORT, MASSA- OI-IUSETTS, A CORP ORATION OF MASSACHUSETTS.

APPARATUS FOR ANNEALING-QSILVER' OR OTHER METALS.

SPECIFICATION forming part of Letters Patent No. 700,101, dated May 13,1902.

Application filed July 1. 1901. Serial 110.66.626. (N0 model.)

To all whom, it may concern.- I 7 Be it known that I; CALEB STICKNEY, a citizen of the United States, residing at Newburyport, in the county of Essex andState of Mas-- sachusetts, have in'ventedcertain new and useful Improvements in-Apparatus for A11- nealing Silver or other Metals, of which the following is a specification, reference being had therein'to the accompanying drawings.

Figure 1 is a perspective view, partly in section, showing one of many practical forms of my invention and the best mode now known to me of applying that principle, 1 is the annealing-furnace, which may be of any desired form, and 2 is a muffle having the usual door 3 atthe front of the furnace. In accordance with my invention muffle 2 is heated exteriorly, and to this end is provided, preferably, on each side with combustionchambers 14, each chamber having a suitable grate 5 and ash-pit 6 thereunder. 1 communicate one with the other above the muffle and also with flue 7 with its smokestack 8. Each chamber 4 is provided with a suitable door 9, and each ash-pit (3 is preferably provided with doors 10.

Muffle 2 is closed, except at its door 3, and' is made of any suitable metal, fire-clay, or other proper. material, door 3 being in practice so loose afit on its frame as to permit the access of oxygen of outside air into the muflie when the apparatus is in use. A hotgas-supply pipe 11 is let intomuffle 2, a now preferred arrangementbeing to have the inner end 12'of the hot-gas-sup'ply pipe 11 at the bottom of: the muffle'. Hot-gas-supply Chambers I pipe 11 leads from hot-gas producer 13 and is provided with a suitable regulating-valve 14. The hot-gas producer 13 comprises a fuelreservoir 15, the bottom portion of which is provided with a fuel-outlet to the fuel-chamber 16, at the bottom of which is a grate 17, under which is an ash-pit 18. The fuel used is one from which a'reducing-gas' is generated when the fuel is burned.

The pipe 11 preferably leads out of an enlargementlt) of chamber 16, which has a vent covered by a cover 19, provided with ahandle 19*, so' that if desired at any time the gas in chamber 16 maybe permitted to escape through the vent.

A forced-blast pipe 20, provided with a regulating-valve 21, leads into ash-pit 18, that is underneath grate 17, and leads from any suitable device (arbitrarilyindicated by the part marked 22)such as a blower, for examplefor.causing a forced blast through pipe 20, ash-pit 18, grate 17, combustionchamber '16, and the gas-supply conduit or pipe 11', so that the gas generated in the combustion-chamber '16 is forced continuously inthemuffle 2. If desired, a steam-pipe 23 may. be used, and thispipe is shown as leading from asource (arbitrarily indicated by the part marked 24) of steam-supply (which may. be .the boiler of an engine) into the forced-draft pipe 20. The purpose of combining the forced-draft pipe and steam-pipe is to mixthe air-blast and steam in regulating proportionswhen steam is required, so that the air-blast introduced into the ash-pit may be moisture-charged, if desired, to the degree desired in operating the apparatus, having particular reference to the variety of the metal to be treated; but in the case of sterling silver or other silver alloy it is not always necessary to impregnate the forced ing cooling medium. Tilting table 3 slides on the horizontal projections a: in front of muilie-door 3, one on either side thereof, and is conveniently connected with the chain at,

which runs over the pulley m suspended in this instance from the ceiling and provided with a counterweightat \Vhen the annealed metal is drawn out from the mufile on the table, the latter is slid forwardly by the attendant until it is far enough beyond the front ends of the projection 00 to permit its front side to drop downwardly and discharge the metal into the air-excluding bath in tank or tub T, the weight of the annealed metal overcoming the resistance of the counterweight, or the attendant pressing down on the front margin of the table. The opposite ends of the table are provided with trunnions 00', which when the table is in its most forward or dumping position bring up against the upturned free sidesm of theprojectionsm, which diverge from their rear ends where they are secured to the furnace. Braces a are used to keep the horizontal projectionsw in place. \Vhen the table is back in place to receive annealed metal drawn out of the muffle, it rests on the diverging horizontal projections m. When the table is slid forward for dumping, the front side of the table passes between the projections m and is kept from displacement by the trunnions at and upturned ends 00 and by the weight of the chain over the pulley. Ends form stops which arrest the forward sliding movement of the slidable receiving-table.

The described means for quickly transferring the annealed metal from the m ullie to the tank is only one of many which may be conveniently used in practice, as will be plain to all mechanics.

By using a proper gas in the muffle during the time the silver alloy is being heated to anneal it oxidation of the alloy is prevented, and if, in accordance with the process invented by lVilliam H. Walker, the annealed silver be quickly removed from the muffle after the annealing operation and quickly plunged into the water therein and the annealed alloy be cooled without exposure to air the silver alloy will be found to be free from fire-surfaces, thus producing a wholly new result in the silversmiths art.

The apparatus herein described has been invented by me mainly for the purpose of carrying out the process of said alker, and I do not claim to be the inventor of the process or method involved in the operation of my muffie.

The metal to be treated is placed in the muflle and is annealed in the presence of an atmosphere, the character of which is largely dependent on the character of the products of combustion coming from combustion-chamber 16.

My present invention is particularly valuable in treating an alloy of silver, as sterling silver, the copper alloy whereof hasbeen heretofore generally oxidized and the annealed silver frequently blistered and made brittle when treated in prior auncaling-muffies. The fire or oxidized surfaces, as Well as the blistered surfaces, have been a source of loss heretofore, for it has been necessary to dissolve off the oxidized surfaces or portions, and I find that by the use of coke for generating the gas my new apparatus is exceedingly useful for annealing or heating to redness sterling silver or silver containing copper or other metals to render the metals soft for further working, to prevent oxidation of the copper therein contained, and to prevent blistering or other deterioration of the metal.

lVhen silver containing copper or containing copper and other metals is placed in the muflie, the muffle is heated to redness from the exterior, and the gas coming from combustion-chamber 16 into the muffle through the pipe or conduit 11 combines with the oxygen of the air in the mullle, so that the gas begins to burn in the mulfle and is consumed according to the formula The gas by its outward pressure thereafter soon displaces the air and ceases to burn, but fills the muffie and so surrounds the metal with hot atmosphere, the chemical character of which depends on the kind of gas generated in the combustion in chamber 16.

The alloy containing copper is annealed in muffle 2 by heating to rednessin the presence of said gas or any other suitable gas, which, owing to its reducing properties and its greater affinity for oxygen and the formation of carbon dioxid and water, prevents the oxidation of the copper in the silver.

If coke be used and a little steam be admitted into the forced-draft pipe, a mixed gas is made in my apparatus by passing a current of air through the forced-draft pipe 20, mixed with steam, the moisture-charged air passing up through the bed of coke (with or without charcoal) when in a state of incandescenee. The combustion in chamber 16 is now complete and results in the formation of a gas containing nitrogen, carbon monoxid, carbon dioxid, hydrogen, and hydrocarbons.

I am the first, so far as I know, to devise an apparatus for annealing silver containing copper.

The \Valker process hereinbefore referred to is set forth in the two applications of William H. alker for United States Letters Patent, said applications being Serial No. 67,709, filed May 24, 1901, and allowed August 10, 1901, and Serial No. 70,320, filed July 31, 1901, and allowed October 19, 1901.

In Serial No. 67,709 said Walker claims- The process of annealing which consists in simultaneously heating an alloy of silver in, and subjecting it to, an hydrogenous reducing-gas diluted with inert gas to prevent oxidation during the heating of the alloy to anneal it.

In said Walkers application Serial No. 70,320 the claim is The herein-described process of producing annealed silver alloys free from fire-surfaces, said process consisting in heating the alloy in a gaseous atmosphere having an annealing temperature, and possessing properties that prevent oxidation during the heating of the alloy; and, secondly, in subjecting such alloy, while still at approximately annealing temperature and substantially unoxidized, to a cooling and air-excluding bath whereby the alloy is cooled without exposure to the air, and the formation of fire-surfaces prevented during the cooling of the annealed alloy.

and a tank for an air-excluding bath; the receiving-table mounted to discharge into said tank.

2. The combination of a muffle; means for heating the muffle exteriorly; a hot-gas-inlet pipe discharging into said muffle; a source of hot-gas supply connected with said hotgas-inlet pipe; means for forcing said gas through said hot-gas-inlet pipe; a receivingtable in front of said muffle, and near the door thereof; diverging supports for the table, and having stops at their front ends; trunnions on opposite ends of the table; a chain attached to the table; a counterweight on the free end of the chain; a pulley over which the chain runs; the table being slidable on its supports between the mufiie and said stops; and being tiltable when slid to the front of said supports.

In testimony whereof I affix my signature in presence of two witnesses.

CALEB STICKNEY.

\Vitnesses:

EDWARD S. BEACH, E. A. ALLEN. 

